LUNAR EXPLORATION BEGINS

Firming Up Plans for Apollo 12

On July 18, 1969, MSC issued the mission requirements document for
Apollo 12, listing the primary purposes of the mission as investigating
the lunar surface environment, emplacing the first Apollo lunar surface
experiments package (ALSEP), obtaining samples from a second lunar mare,
and enhancing the capability for manned lunar exploration. Major changes
from Apollo 11 included the possible use of a hybrid trajectory* rather than a free-return trajectory and
scheduling two periods of lunar surface exploration by both crewmen.
Five possible landing sites were specified, including site 5 (the
western mare site preferred by the scientists) and Surveyor
III.46

After Sam Phillips designated the Surveyor as the spot for Apollo 12 to
land, mission planning focused on the problems of precision landing (see
above), deployment of the ALSEP, geological observations and sample
collection, and examination of the Surveyor and its surroundings.47 Although some at MSC believed that returning
some components of the Surveyor was of considerable importance, other
surface activities were given higher priority48 - probably in deference to the scientists.
(The site had been unanimously rejected by the Group for Lunar
Exploration Planning, who considered the inert spacecraft to be an
"attractive nuisance" that would likely divert the astronauts
from more important work.49) Deployment
of the first ALSEP was high on the priority list, since scientists had
been disgruntled by the decision to fly a simplified package of surface
instruments on Apollo 11. [see Chapter
8] Geologists wanted the Apollo 12 astronauts to be somewhat
more selective than their predecessors in collecting samples and
stressed the importance of documenting (photographing and describing)
them. They also preferred more rocks and less dust, if possible. To
determine what the astronauts should do on and around Surveyor
III, MSC had already begun discussions with Hughes Aircraft
Company.

* Hybrid trajectories were
fuel-saving flight paths which, unlike free-return trajectories, would
not return the spacecraft to earth if the service module's main
propulsion system failed to put it into lunar orbit. They were designed
so that in case of such a failure the lunar module's descent engine
could correct the resulting flight path (which might put the spacecraft
with its three occupants into solar orbit) for return to earth.